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authorJeremy Kerr <jk@codeconstruct.com.au>2023-04-05 12:41:49 +0300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2023-04-28 09:19:01 +0300
commit7dc2e0a875645a79f5c1c063019397e8e94008f5 (patch)
treecadca558dab0a9384a8a715379a2209dd52868e4 /drivers/i3c
parent5844564143575a8dbcbcece0084da059faeca5df (diff)
downloadlinux-7dc2e0a875645a79f5c1c063019397e8e94008f5.tar.xz
i3c: Allow OF-alias-based persistent bus numbering
Parse the /aliases node to assign any fixed bus numbers, as is done with the i2c subsystem. Numbering for non-aliased busses will start after the highest fixed bus number. This allows an alias node such as: aliases { i3c0 = &bus_a, i3c4 = &bus_b, }; to set the numbering for a set of i3c controllers: /* fixed-numbered bus, assigned "i3c-0" */ bus_a: i3c-master { }; /* another fixed-numbered bus, assigned "i3c-4" */ bus_b: i3c-master { }; /* dynamic-numbered bus, likely assigned "i3c-5" */ bus_c: i3c-master { }; If no i3c device aliases are present, the numbering will stay as-is, starting from 0. Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au> Link: https://lore.kernel.org/r/20230405094149.1513209-1-jk@codeconstruct.com.au Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/i3c')
-rw-r--r--drivers/i3c/master.c30
1 files changed, 25 insertions, 5 deletions
diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 04d6d54d2ab8..08aeb69a7800 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -21,6 +21,7 @@
static DEFINE_IDR(i3c_bus_idr);
static DEFINE_MUTEX(i3c_core_lock);
+static int __i3c_first_dynamic_bus_num;
/**
* i3c_bus_maintenance_lock - Lock the bus for a maintenance operation
@@ -419,9 +420,9 @@ static void i3c_bus_cleanup(struct i3c_bus *i3cbus)
mutex_unlock(&i3c_core_lock);
}
-static int i3c_bus_init(struct i3c_bus *i3cbus)
+static int i3c_bus_init(struct i3c_bus *i3cbus, struct device_node *np)
{
- int ret;
+ int ret, start, end, id = -1;
init_rwsem(&i3cbus->lock);
INIT_LIST_HEAD(&i3cbus->devs.i2c);
@@ -429,8 +430,19 @@ static int i3c_bus_init(struct i3c_bus *i3cbus)
i3c_bus_init_addrslots(i3cbus);
i3cbus->mode = I3C_BUS_MODE_PURE;
+ if (np)
+ id = of_alias_get_id(np, "i3c");
+
mutex_lock(&i3c_core_lock);
- ret = idr_alloc(&i3c_bus_idr, i3cbus, 0, 0, GFP_KERNEL);
+ if (id >= 0) {
+ start = id;
+ end = start + 1;
+ } else {
+ start = __i3c_first_dynamic_bus_num;
+ end = 0;
+ }
+
+ ret = idr_alloc(&i3c_bus_idr, i3cbus, start, end, GFP_KERNEL);
mutex_unlock(&i3c_core_lock);
if (ret < 0)
@@ -2606,7 +2618,7 @@ int i3c_master_register(struct i3c_master_controller *master,
INIT_LIST_HEAD(&master->boardinfo.i2c);
INIT_LIST_HEAD(&master->boardinfo.i3c);
- ret = i3c_bus_init(i3cbus);
+ ret = i3c_bus_init(i3cbus, master->dev.of_node);
if (ret)
return ret;
@@ -2830,8 +2842,16 @@ void i3c_dev_free_ibi_locked(struct i3c_dev_desc *dev)
static int __init i3c_init(void)
{
- int res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
+ int res;
+
+ res = of_alias_get_highest_id("i3c");
+ if (res >= 0) {
+ mutex_lock(&i3c_core_lock);
+ __i3c_first_dynamic_bus_num = res + 1;
+ mutex_unlock(&i3c_core_lock);
+ }
+ res = bus_register_notifier(&i2c_bus_type, &i2cdev_notifier);
if (res)
return res;